PBS process at max CPU

Ever so often, I find my MacBook Pro attempting to lift off from my desk. The fan is running at full tilt but there's nothing going on.

Most of the time, I find that the "pbs" service is eating all available CPU time. Killing the service just makes it restart and resume the CPU consuption a few seconds later, nothing else I can detect happens.

I understand that the pbs process is a helper tool, and as far as I can detect it's job is to populate the services menu. I can't understand why that should be such an CPU intensive task. Even if it is, I'd rather live without it then have it consuming all the available CPU time. It's not to conserve power, but the constant fan noise drives me crazy.

I assume that this is not normal behaviour. How can I find out what causes it to run like crazy? And if it is normal, is it possible to throttle the process a little (automatically)? I can live with a slower service as long as it's reasonably quiet.